Plate Tectonics

Brainstorm Write down everything you know about plate tectonics in your class notes!

Earth’s Plates Earth’s lithosphere is broken into separate sections called plates. These pieces of lithosphere float on the asthenosphere and interact with each other.

Plate Tectonics Theory The theory that explains how Earth’s plates move and change shape is known as The Plate Tectonics Theory. Plate tectonics explains why seafloor spreading and continental drift occur.

Convection Currents The rising and falling of parts of Earth’s mantle in a cycle. Less dense parts rise because of hot temperatures. More dense parts sink because of cool temperatures.

This process is powered by heat from Earth’s core. The cycle of convection currents pushes and pulls the plates causing them to move. Convection Cells. This process is powered by heat from Earth’s core.

Plate Movement Plates move about 1 cm a year! Global Positioning System (GPS) satellites can track the motion of plates.

Modern Evidence for Plate Tectonics GPS Data on plate motion. Earthquakes and volcanoes occur mostly where plates meet.

All Known Earthquakes and Volcanoes